Rapper 2 Chainz’s set was filled with the explicit party anthems that have made him a star (“Birthday Song,” “I’m Different,” “R.I.P.”). It made for one of the days most engaged, excitable crowds. People were dancing up front, in back and in trees. (Really.)

Just before he left the stage, he asked for “a moment of silence for the Houston firefighters who lost their lives yesterday.” It was as good a reason as any to put the party on pause.